Method and apparatus for electrolytically recovering metals

ABSTRACT

A depositer for electrolytically recovering metal from the bed of a body of water includes a submersible housing with a closed top end and an open bottom end and is operable to lodge by walls defining the sides of the housing within the bed to form a closed chamber containing a portion of the bed and water. The housing serves as the anode of the depositor and is electrically connected with an energy source for supplying direct current thereto. A plurality of rods depending from the top end extend into the chamber, serve as the cathodes, and are also connected with the energy source. Mounted on the inside wall of the chamber are a plurality of sieves adapted to hold a dissolvable chemical used to increase the conductivity of water captured in the chamber. A pump agitator suspended from the top and positioned within the chamber draws material from the bed and circulates it within the chamber to thoroughly mix the chemical with the captured water and bed to more readily ionize the metal to be recovered. As a suitable electric potential is applied between the anode and cathodes, the ionized metal confined within the chamber deposits upon the cathode rods.

United States Patent [191 Mortell [451 Feb. 27, 1973 METHOD ANDAPPARATUS FOR ELECTROLYTICALLY RECOVERING METALS [76] Inventor: CharlesH. Mortell, 6929 South Main Street, Rockford, Ill.

[22] Filed: Dec. 21, 1970 [21] Appl. No.: 99,784

[52] US. Cl ..204/105 R, 204/109, 204/271, 204/272, 204/273, 204/275,204/278 [51] Int. Cl ..C22d l/00, C22d l/02, C23b 5/68 [58] Field ofSearch ..204/271, 273, 272, 275, 233, 204/278, 143 R, 105, 109,114

Primary Examiner-John H. Mack Assistant Examiner-R. L. AndrewAttorney-Wolfe, Hubbard, Leydig, Voit & Osann .igg/jgl lllmlluhlmm [5 7ABSTRACT A depositer for electrolytically recovering metal from the bedof a body of water includes a submersible housing with a closed top endand an open bottom end and is operable to lodge by walls defining thesides of the housing within the bed to form a closed chamber containinga portion of the bed and water. The housing serves as the anode of thedepositor and is electrically connected with an energy source forsupplying direct current thereto. A plurality of rods depending from thetop end extend into the chamber, serve as the cathodes, and are alsoconnected with the energy source. Mounted on the inside wall of thechamber are a plurality of sieves adapted to hold a dissolvable chemicalused to increase the conductivity of water captured in the chamber. Apump agitator suspended from the top and positioned within the chamberdraws material from the bed and circulates it within the chamber tothoroughly mix the chemical with the captured water and bed to morereadily ionize the metal to be recovered. As a suitable electricpotential is applied between the anode and cathodes, the ionized metalconfined within the chamber deposits upon the cathode rods.

9 Claims, 5 Drawing Figures PATENTED FEB 2 7 I973 SHEET 2 0F 2 METHODAND APPARATUS FOR ELECTROLYTICALLY RECOVERING METALS BACKGROUND OF THEINVENTION This invention relates to electrolytic depositors of the typeadapted to recover valuable or precious metals such as gold, silver ormercury by chemically treating an aqueous solution containing the metalto increase the conductivity of the solution so that it becomes asuitable electrolyte and, thereafter, applying a direct current,electric potential between positive and negative electrodes immersed inthe solution to cause electron flow between the electrodes so that adeposit of a selected metal forms on the negative electrode or cathode.

SUMMARY OF THE INVENTION The general object of the present invention isto provide a new and improved electrolytic depositor of the foregoinggeneral character which is particularly adapted to be submerged within abody of water, such as a stream, and operated to recover a metal such asgold settled on the stream bed.

A further object is to provide a depositor which is adapted to lodge inthe stream bed to form a closed chamber in which water and a portion ofthe bed are captured. An associated object is to provide means withinthe chamber for treating the captured water and bed so they becomeelectrically conductive such that when an electric potential is appliedbetween the electrodes electrons flow to the cathode and deposit themetal.

which is portable so that it may be moved easily from place to place onthe stream bed.

The invention also resides in the novel manner of recovering the metaldirectly from the bed of the body of water.

Other objects and advantages will become apparent from the followingdetailed description when taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of adepositor embodying the novel features of the present invention showingthe depositor lodged in the bed of a stream and being operated from aboat to electrolytically recover metals from the stream bed.

FIG. 2 is an enlarged plan view of the depositor shown in FIG. 1.

FIG. 3 is an enlarged fragmentary cross-sectional view takensubstantially along line 3-3 of FIG. 2.

FIG. 4 is an enlarged cross-sectional view taken substantially alongline 44 of FIG. 2.

FIG. 5 is an enlarged fragmentary cross-sectional view takensubstantially along the line 5-5 of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in thedrawings for purposes of illustration, the invention is embodied in adepositor 10 for electrolytically recovering metals dissolved, suspendedor deposited in an electrically conductive solution called anelectrolyte ll. Electrolytic recovery of metals is accomplished by theapplication of a direct-current, electric potential between electrodesimmersed in the electrolyte. During electrolysis, positively andnegatively charged ions, respectively accept and give-up electrons atthe electrodes to maintain a state of balance in the electrolyte byoffsetting the effect caused by the application of the direct current.The positively charged ions, usually the metal ions, are drawn to anegative electrode or cathode 13 and accept electrons sufficient toreduce the ion to its metallic form which plates on the cathode. Thenegatively charged ions, on the other hand, are drawn to a positivelycharged electrode or anode 14 to give-up sufficient electrons totransform the ion into its normal molecular state which is usuallygaseous in nature. After a sufficient quantity of metal has plated onthe cathode, the latter can be removed from the electrolyte and themetal scraped from the cathode. Thus, when metals are recovered by usingan electrolytic process, the ions in the electrolyte, in effect, carrythe electric current through the electrolyte to the electrodes byaccepting electrons and plating at the cathode, and giving-up electronsand being driven off as a gas at the anode.

In electrolytic plating, a metal present in the electrolyte llaccumulates at the cathode 13 according to that metals tendency toaccept electrons. This tendency is directly related to the conductivityof the electrolyte and the voltage applied between the electrodes. Theconductivity of the electrolyte solution depends upon the concentrationof ion radicals in the solution because it is these radicals that acceptand give-up electrons to cause an electron flow between the electrodes.Since salts tend to disassociate into their ion radicals when dissolvedin water, the addition of a salt to water necessarily increases theconductivity of the electrolyte. Thus, by dissolving a salt in theelectrolyte and applying the proper voltage potential between theelectrodes of a depositor containing a selected metal to be recovered,the metal deposits on the cathode of the depositor. For instance, torecover gold, either of the salts zinc chloride, magnesium chloride orpotassium cyanide added to water will enable sufficient quantities ofelectrons to flow through the resulting solution, upon the applicationof a selected voltage potential, and cause any gold contained in thesolution to deposit on the cathode. For this purpose, a current orelectron flow in the range of 10 to 15 amperes per square inch ofcathode surface area results in a depositing of gold from theelectrolyte onto the cathode. To facilitate the removal of the gold fromthe cathodes and accelerate the initial depositing of the gold, a filmof mercury may be placed on the cathode.

In accordance with the primary aspect of the present invention, thedepositor 10 is adapted to operate under the surface of a body of water15 such as a stream to electrolytically recover precious metals thathave settled in various locations on the stream bed. For this purpose,the depositor includes a submersible housing 16, at least one anode 14and at least one cathode 13, both of which are contained within thehousing. The latter is operable, when lowered through the water, tolodge within the stream bed to define a chamber 17 captivating aquantity of the stream '5 water adjacent the bed in addition to aportion of the bed itself. A means 19 (FIG. 4) operates to deposit achemical within the chamber to ionize the captivated water and bed tocreate the electrolyte solution 11 through which electrons can flow.Thereafter, the material in the captivated bed is circulated throughoutthe chamber to mix the electrolyte thoroughly with the precious metalspresent such that, as a direct current, voltage potential is appliedbetween the anode and cathode, substantially all of the metal presentplates out on the cathode. When the supply of the metal is exhausted atone location in the stream bed, the depositor may be lifted from the bedand easily transported to another location. Thus, the present inventionprovides a simple and effective instrument which is adapted toefficiently and economically recover gold or any other desired metaldirectly from the bed of a body of water.

To recover a metal directly from the bed of a stream, the depositor istransported by means of a boat 20 or other suitable water vehicle(FIG. 1) to a selected position above a desired location on the bed andis lowered by two nylon lines 21 through the water to lodge in thestream bed captivating a quantity of water and bed in the chamber. Inthe present instance, ionization of the captivated water and bed iseffected by the dissolution of the disassociating chemical, zincchloride, which is contained within the depositing means, herein, fourperforated boxes or sieves 19 mounted on the housing wall within thechamber 17. The dissolution of the zinc chloride is accelerated by aflow of the captivated water and material expelled by an agitator in theform of an electrically operated sump pump 23 connected to the top ofthe housing and resting within the chamber on the stream bed. The flowis directed out of a nozzel 24 positioned in the center of the chamberin a circular path through the chamber thoroughly mixing the zincchloride and water into the electrolyte solution 11 which is suitable toconduct electron flow between the anode and cathode upon the applicationof the direct current, electric potential. Once the latter is applied,the electron flow between the electrodes quickly ionizes any of themetal present in the circulating material and causes it to plate out ordeposit on ten rods 25 extending into the chamber and serving as thecathodes 13 while gases driven out of the electrolyte rise through ahose 26 connected to the top of the housing and leading to the surfaceto vent in the atmosphere. After the supply of the metal present in thebed is recovered, the depositor may be raised to the surface to removethe cathode rods and collect the deposited metal.

More specifically, the depositor housing 16 is formed in the shape of athin-walled, copper cylinder with its bottom end 27 open and its upperend closed by a circular copper lid 29. The latter is fastened to thehousing by means of a watertight, interlocking double seam 30 (FIG. 3)which is formed at the periphery of the lid integrally with the top edgeof the housing wall to reduce the loss or dilution of the electrolyte 11within the chamber 17 during electrolysis. Mounted on the outside wallof the housing is an electrical connector 31 (FIG. 3) receiving a lead33 which connects the housing with a direct current source electricalenergy (not shown). Thus, the housing, including both the cylinder andlid, serves as the anode 14 of the depositor 10.

Extending through the lid 29 into the housing chamber 17 and terminatingeven with the bottom edge of the housing wall are the ten cathode rods25 (FIGS. 2 and 3) which are angularly spaced from each other inwardlyof the periphery of the lid. Preferably, the cathode rods are made ofcarbon, carbon steel or copper and are electrically interconnected witheach other through a wire 34 which also serves to connect one of therods to the negative side of the direct current, energy source (seeFIGS. 2 and 3). Consequently, when the depositor 10 is lowered into thewater 15 to lodge into the bed, a portion of the ends of the rods sticksinto the bed to the same extent as the housing wall. Thus, with thedepositor activated, an electric potential also exists through a portionof the bed to help ionize metal particles found therein.

To mount the cathode rods 25 within the chamber 17, the lid 29 includesten cylindrical collars 35 (FIG. 3) which extend longitudinally throughand are welded to the lid in positions angularly spaced from each otherinwardly of the periphery of the lid. Telescoped into each of thecollars is an insulating sleeve 36 which includes an outwardlyprojecting annular flange 37 fitting over the top of the sleeve toelectrically insulate the cathode rods from the anode 14 and therebyprevent short circuits within the depositor 10. Each sleeve is heldwithin one of the collars by an open-ended cap 39 (FIG. 3) threaded overthe top of the collar to engage the flange and squeeze it against thetop of the collar. The rods 25 are telescoped through the sleeves in awatertight engagement therewith and extend into the chamber and areadjustable within the latter by loosening the cap, grasping the outerexposed portion of the rod and pulling thereon to select the length ofthe rod projecting into the chamber. Similarly, the rods may be removedfor scraping to recover metals deposited thereon. Thus, the rods aremounted through and connected to the lid in a watertight andelectrically insulated manner to project into the chamber for theelectrolytic recovery of the metal.

To chemically treat the water trapped within the chamber to increase itsconductivity, the four sieves 19 are mounted by brackets 40 on the innerwall of the chamber. The sieves are angularly spaced from each other andlocated in a horizontal plane intersecting the approximate center of thechamber as illustrated in FIGS. 2 and 4. Zinc chloride placed within thesieves is preferred over other chemicals, such as potassium cynide,because the electrolyte thus created will not act as a pollutant whenreleased into the stream.

To accelerate the ionization of the metal present in the stream bed bydissolving and mixing the zinc chloride throughout the chamber 17, thepump 23 sucks in water and material from the stream bed through intakeports (not shown) in the lower base portion 41 of the pump. Thesucked-in water and material is pumped out into the chamber through anupstanding tube 43 which is connected by its lower end to a threadedorifice 44 in the base of the pump and extends upwardly therefromparalleling the pump to an upper end 45 positioned in the centralportion of the chamber (FIG. 4). Fastened on the upper end is the nozzelor elbow 24 which directs the flow of material and water in a circularpath through the chamber.

The pump 23 is carried on the end of a pipe 46 which is connected to thelid 29 by means of a circular support plate 47 (FIG. 5) with anintegrally formed, internally threaded sleeve 49 extending into thechamber 17 to have the upper end 50 of the pipe threaded into it.Running through the center of the pipe and connected to the pump is anelectric cord 51 which carries an alternating current from an energysource (not shown) to the pump. The cord enters the pipe through anaperature 53 in the center of the lid, the aperature being sealed by awatertight rubber grommet 54 sandwiched around the lid at the peripheryof the aperature and surrounding the cord.

The plate 47 is fastened by screws 55 to four angleirons 56 each ofwhich is welded to the inside surface of the lid 29 and extends to theperiphery thereof from an end 57 angularly spaced from the other ironsand tangentially of a defined circular area in the central portion ofthe lid as shown in FIG. 2. The angle-irons give additional support tothe lid to prevent the latter from denting inwardly under the weight ofthe pump 23. The screws are threaded into an angle-iron leg 59 whichfits flat against the lid, as shown in FIG. 5, to space the plate fromthe lid. Located between the plate and the angle-irons is a ring-shapedgasket 60 electrically insulating the plate, pipe and pump from the lid.A short circuit through the screws is prevented bya rubber grommet 61inserted into each of the screw holes around the screws. An end portion63 of each grommet overlaps the edge of the hole to act as an insulatingwasher for the head of the screw.

To provide a vent for the gases collecting at the anode 14 duringelectrolysis, the lid includes an opening 64 (FIG. 4) with a threadedhose coupling 65 mounted around the opening which is adjacent theperiphery on the outer surface of the lid 29. The hose 26 is connectedto the coupling and leads to the waters surface providing an atmosphericvent for the gases driven out of the electrolyte during the depositingprocess.

It will be observed from the above that the present invention providesan electrolytic depositor of new and novel construction and one whichcan be used in a new and novel manner to recover precious metalsdirectly from the bed of a stream in an economic and efficientoperation. This is accomplished by lodging the depositor in the bed ofthe stream in the desired location to trap a quantity of water and bedwhich is treated with zinc chloride thus creating the electrolytesolution lll for the electrolytic recovery of any metal found in the bedcontained within the chamberIAfter all the metal at one location hasplated on the cathode rods 25, the depositor can be easily transportedto another location in the bed and the process repeated.

1 claim as my invention:

ll. An electrolytic depositor for removing metals from the bed of a bodyof water, said depositor comprising a submersible housing with a closedtop end and sidewalls and an open bottom end, said housing beingoperable when dropped into the body of water to lodge by its sidewallsin the bed forming a chamber containing water and a portion of the bed,said depositor including at least one anode communicating with theinterior of said housing, means for connecting said anode to a source ofdirect-current electrical energy, at least one cathode disposed withinsaid housing and electrically insulated from said anode, meanselectrically connecting said cathode with said sourceof electricalenergy, means supporting said cathode within said housing whereby thecathodes form depositors for collecting the metals when a suitableelectric potential is applied between said anode and the cathodes, anagitating means operable to stir material containing the metal loosefrom the bed to circulate within said chamber, and a chemical depositingmeans operable to deposit chemicals within said chamber to increase theconductivity of the water contained within said chamber.

2. A depositor as defined in claim 1 in which said housing is the anode.

3. An electrolytic depositor for removing metals from the bed of a bodyof water, said depositor comprising a submersible housing with a closedtop end and sidewalls and an open bottom end, said housing beingoperable when dropped into the body of water to lodge by its sidewallsin the bed forming a chamber containing water and a portion of the bed,means for connecting said housing to a source of electrical energywhereby said housing constitutes the anode of the depositor, a pluralityof cathodes disposed within said housing, means electricallyinterconnecting said cathodes with each other and connecting one of saidcathodes to said source of electrical energy, means supporting saidcathodes within said housing while electrically insulating the cathodesfrom the housing whereby the cathodes form depositors for collecting themetals when a suitable electric potential is applied between said anodeand the cathodes, an agitating means operable to stir materialcontaining the metal loose from the bed to circulate within saidchamber, and a chemical depositing means operable to deposit chemicalswithin said chamber to increase the conductivity of the water containedwithin said chamber.

4. A depositor as defined by claim 3 wherein said agitating meanscomprises a pump for sucking material containing the metal from the bedand expelling the material in the upper end of the chamber so that itcirculates through the chamber, said pump being suspended within saidchamber and connected to a suitable energy providing means which isoperable to activate said pump.

5. A depositor as defined by claim 3 wherein said cathodes are elongatedvertical rods and the lower ends of said cathodes terminate within saidchamber at a position even with the bottom edge of said sidewalls tolodge within said bed.

6. A depositor as defined by claim 5 wherein said supporting meansdetachably connects said cathodes to said top to permit the cathodes tobe easily removed to strip deposited metal therefrom.

7. A depositor as defined in claim 3 including means communicatingbetween said chamber and the at mosphere above the body of water topermit gases to escape from said chamber.

8. A method of recovering metals contained in material on the bed of abody of water, said method comprising the steps of submerging anelectrolytic electric potential to the depositor to draw the metals tothe negative electrode from the water and the material on the bed.

9. The method as defined in claim 8 wherein the depositor includes ahousing, one of said electrodes being a portion of said housing, and thecirculating of said material being done within said housing.

2. A depositor as defined in claim 1 in which said housing is the anode.3. An electrolytic depositor for removing metals from the bed of a bodyof water, said depositor comprising a submersible housing with a closedtop end and sidewalls and an open bottom end, said housing beingoperable when dropped into the body of water to lodge by its sidewallsin the bed forming a chamber containing water and a portion of the bed,means for connecting said housing to a source of electrical energywhereby said housing constitutes the anode of the depositor, a pluralityof cathodes disposed within said housing, means electricallyinterconnecting said cathodes with each other and connecting one of saidcathodes to said source of electrical energy, means supporting saidcathodes within said housing while electrically insulating the cathodesfrom the housing whereby the cathodes form depositors for collecting themetals when a suitable electric potential is applied between said anodeand the cathodes, an agitating means operable to stir materialcontaining the metal Loose from the bed to circulate within saidchamber, and a chemical depositing means operable to deposit chemicalswithin said chamber to increase the conductivity of the water containedwithin said chamber.
 4. A depositor as defined by claim 3 wherein saidagitating means comprises a pump for sucking material containing themetal from the bed and expelling the material in the upper end of thechamber so that it circulates through the chamber, said pump beingsuspended within said chamber and connected to a suitable energyproviding means which is operable to activate said pump.
 5. A depositoras defined by claim 3 wherein said cathodes are elongated vertical rodsand the lower ends of said cathodes terminate within said chamber at aposition even with the bottom edge of said sidewalls to lodge withinsaid bed.
 6. A depositor as defined by claim 5 wherein said supportingmeans detachably connects said cathodes to said top to permit thecathodes to be easily removed to strip deposited metal therefrom.
 7. Adepositor as defined in claim 3 including means communicating betweensaid chamber and the atmosphere above the body of water to permit gasesto escape from said chamber.
 8. A method of recovering metals containedin material on the bed of a body of water, said method comprising thesteps of submerging an electrolytic depositor in the body of water, saiddepositor including at least one positive electrode and at least onenegative electrode, drawing material containing the metal to be removedfrom the bed, circulating the material within the depositor, applying achemical to increase the conductivity of the water and cause dissolvedmetal to deposit on the negative electrode upon the application of asuitable electric potential, and applying a suitable electric potentialto the depositor to draw the metals to the negative electrode from thewater and the material on the bed.
 9. The method as defined in claim 8wherein the depositor includes a housing, one of said electrodes being aportion of said housing, and the circulating of said material being donewithin said housing.